1. Field of the Invention
This invention relates to a cyclic sulfur compound (cyclic polysulfide), and more particularly, to a cyclic sulfur compound represented by the formula, ##STR3## wherein R is --CH.sub.2 CH.sub.2 O).sub.n CH.sub.2 CH.sub.2 --, m is an integer of 2 to 4 and n is an integer of 1 to 3, and a process for producing the same.
2. Description of the Prior Art
Cyclic sulfur compounds containing at least two sulfur atoms are not so much present in nature. However, these are known Nereistoxin which is the toxin of Lumbriconereis heteropoda (a kind of marine animal), Lenthionine which is the fragrant ingredient of Cortinellus shiitake, 1,2,4,6-tetrathiepane contained in Chondria californica of red alga which exhibits antibacterial and antifungous activities, and the like. Attention is directed to a cyclic sulfur compound as one of the compounds having a physiological activity. In addition, in view of its position in organic industrial chemistry, the cyclic sulfur compound can be utilized as a crosslinking agent instead of sulfur per se or as a monomer for preparing a polysulfide polymer having good resistance to weather and oil.
Cyclic sulfur compounds represented by the formula (I) wherein R consists of a hydrocarbon (CH) have already been known, and the following synthesis methods have been known:
(1) Davis et al's method [F. O. Davis and E. M. Fettes, J. Am. Chem. Soc., 70, 2611 (1948)], PA0 (2) Affleck et al's method [J. G. Affleck and G. Dougherty, J. Org. Chem., 15, 865 (1950)], PA0 (3) Cragg et al's method [R. H. Cragg and A. F. Weston, Tetrahedron Letters, 655 (1973)], PA0 (4) Swan et al's method [B. Milligam and J. M. Swan, J. Chem. Soc., 2901 (1965)], PA0 (5) Harpp et al's method [D. N. Harpp, K. Stelion and T. H. Cham, J. Am. Chem. Soc., 100, 1222 (1978); J. A. Moore, J. E. Kelly, D. N. Harpp and T. G. Back, Macromolecules, 10, 718 (1977)], PA0 (6) Harpp et al's method [D. N. Harpp and Alessandro Granata, J. Org. Chem., 44, 4144 (1979)], and the like.
The present inventors have paid their attention to the fact that such silyl sulfides as used in the Abel et al reaction [E. W. Abel and D. A. Armitage, J. Chem. Soc., 5975 (1964)] and such tin sulfides as used in the Wardell et al reaction [J. L. Wardell and P. L. Clarke, J. Organometal Chem., 26, 345 (1971)] have a high reactivity in view of the fact that in the Abel et al reaction, dibutyl disulfide is obtained in high yield by the reaction between butylthiotrimethyl silane and bromine and that in the Wardell et al reaction, di-4-toluyl tetrasulfide is obtained in high yield by the reaction between tripropyltin-4-toluyl sulfide and sulfur monochloride, and have conducted extensive research on the synthesis of cyclic sulfur compounds to find a novel process for producing novel cyclic sulfur compounds in high yield.